Influences of aeration induced turbulence on growth and competition of Microcystis and Scenedesmus in the presence of sediments with varying particle sizes     

Qiang HE  Yiyao WANG  Ming LI 《海洋湖沼学报（英文）》2022,(1):142-152

Aeration is an important measure to prevent cyanobacterial growth in eutrophic lakes and reservoirs. The purpose of this study is to clarify the influence of ae...  相似文献   

一个基于“部分通量订正”的热带太平洋和全球大气耦合模式及它的性能检验     

薛洪斌  王业桂  周广庆  张铭 《热带气象学报》2006,22(6):560-566

基于“部分通量订正”同步耦合方案，将中国科学院大气物理研究所发展的九层大气环流格点模式与十四层热带太平洋环流模式耦合并成功积分40年。结果表明，模式没有明显的“气候漂移”现象，同时模式能模拟出与未耦合的海气模式接近的气候平均态及其季节变化，及与观测接近的年际气候变率。这种年际变率在热带太平洋地区表现为类似于ENSO事件的时空分布特征。  相似文献   

2013年3月11日阿图什5．2级地震灾害损失评估和房屋震害特征分析     

李帅  谭明  吴国栋  艾力夏提·玉山  宋立军 《内陆地震》2013,(4):341-347

2013年3月11日新疆阿图什发生慨5．2地震,震中烈度Ⅵ度,地震没有造成人员伤亡,个别民宅倒塌,造成直接经济损失2397万元。结合此次地震考察评估工作,分析此次地震造成经济损失的震害原因。从房屋破坏、房屋建筑场地条件和抗震安居工程三点,描述了此次地震的震害特征,与新疆伽师、莎车等具有相同地质条件的地区进行震后对比,并结合2009年4月22日发生的新疆阿图什Ms5．0地震,提出了对此次地震的认识与建议。  相似文献   

扩展的倾斜角和倾斜角总水平导数方法     

王明  郭志宏  骆遥  罗锋 《地球物理学进展》2013,28(3)

为了突出显示重磁场中地质体分布、断裂构造特征等信息,使图像显示错落有序、层次分明、清楚直观,有利于解释人员从不同角度认识重磁场异常特征.本文通过分析倾斜角概念,根据反余切函数特性,提出了扩展的倾斜角(iTdr)和倾斜角总水平导数(iTdr_Thdr)方法,来增强重磁异常信息,突出异常形状特点,以便于识别重磁异常中地质体边界和提取地质体分布、断裂构造平面展布特征等信息.理论模型和实际资料对比分析表明该方法简单、实用、具有较好的识别效果和较高的分辨能力,能够获取丰富的地质信息,对识别地质体边界、划分大地构造单元、确定断裂带和地质构造走向等具有实际意义.  相似文献   

Research on wind-induced responses of a large-scale membrane structure   总被引：1，自引：1，他引：0  

Zhou Xuanyi  Han Zhihui  Gu Ming  Zhang An-an  Zhang Weiyu  Fang Wei 《地震工程与工程振动(英文版)》2013,12(2):297-305

The wind-induced responses of a large-scale membrane structure, Expo Boulevard, are evaluated in this study. To obtain the wind pressure distribution on the roof surface, a wind tunnel test is performed. A brief analysis of wind pressure on the membrane roof is conducted first and then an analysis of the wind-induced responses of the structure is carried out using a numerical integral method in the time domain. In the process of calculation, the geometrical nonlinearity is taken into account. Results indicate that mean, RSM and peak values of the structure responses increase nonlinearly while the approaching flow velocity increases. Strong nonlinear characteristics are observed in the displacement responses, whereas the responses of nodal stress and cable axial force show minimal nonlinear properties when the membrane structure is subjected to wind loads. Different values of the damping ratio only have a minimal impact on the RSM response of the structure because the background component is a dominant part of the total dynamic response and the resonant component is too small. As the damping ratio increases from 0.02 to 0.05, the RMS responses of vertical displacement, nodal stress and cable axial force decrease by 8.1%, 6.7% and 17.9%, respectively. Since the mean component plays a significant role in the wind-induced response, the values of the gust response factor are not high for Expo Boulevard.  相似文献   

Hydrological characteristics of vegetated river flows: a laboratory flume study     

John Z. Shi  Yan-Hong Li  Jocelyne M.R. Hughes  Ming Zhao 《水文科学杂志》2013,58(5):1047-1058

Abstract

Laboratory flume experiments were undertaken to measure the vertical profiles of mean flow velocity for three different flow discharges and four different stem densities of Hydrilla verticillata. The data were used to calculate three parameters, namely Manning's roughness coefficient, the Reynolds number and the Froude number. In addition, empirical equations were obtained for the vertical distribution of measured flow velocity within the transitional zone and above the plant canopy. The results show that: (a) the vertical distribution of measured flow velocity exhibits three zone profiles; (b) Manning's roughness coefficient decreases with increasing depth-averaged flow velocity; (c) the relationship between Manning's roughness coefficient and the depth-averaged flow velocity is within the smooth left inverse curve; (d) Manning's roughness coefficient significantly changes with increasing density of Hydrilla; (e) the Froude number is independent of the density of Hydrilla; and (f) both the Reynolds number and the Froude number increase with increasing depth-averaged flow velocity.

Citation Shi, J.Z., Li, Y.-H., Hughes, J.M.R., and Zhao, M., 2013. Hydrological characteristics of vegetated river flows: a laboratory flume study. Hydrological Sciences Journal, 58 (5), 1047–1058.

Editor Z.W. Kundzewicz  相似文献   

基于行政隶属关系树状图的地名消歧方法     

朱少楠  张雪英  李明  王宇 《地理与地理信息科学》2013,29(3)

同一地名映射不同物理空间位置的地名歧义现象普遍存在,地名消歧是指为地名分配唯一地理位置的过程.欧美国家的地名数据库和相关知识库比较完善,提出一系列通用或适宜个别语种的地名消歧方法.由于我国当前缺乏类似的高质量数据资源,难以直接引入这些方法解决中文地名消歧问题.该文提出在地名识别和地名匹配的基础上,通过构建歧义地名行政隶属关系树状图,利用上下文相关地名在树状图中出现的子节点数,判断歧义地名指向的地理位置.实验表明,该方法简单易行,而且可以达到较好的消歧效果.  相似文献   

Application of a multi‐temporal,LiDAR‐derived,digital terrain model in a landslide‐volume estimation     

Chih‐Ming Tseng  Ching‐Weei Lin  Colin P. Stark  Jin‐Kin Liu  Li‐Yuan Fei  Yu‐Chung Hsieh 《地球表面变化过程与地形》2013,38(13):1587-1601

Sediments produced by landslides are crucial in the sediment yield of a catchment, debris flow forecasting, and related hazard assessment. On a regional scale, however, it is difficult and time consuming to measure the volumes of such sediment. This paper uses a LiDAR‐derived digital terrain model (DTM) taken in 2005 and 2010 (at 2 m resolution) to accurately obtain landslide‐induced sediment volumes that resulted from a single catastrophic typhoon event in a heavily forested mountainous area of Taiwan. The landslides induced by Typhoon Morakot are mapped by comparison of 25 cm resolution aerial photographs taken before and after the typhoon in an 83.6 km² study area. Each landslide volume is calculated by subtraction of the 2005 DTM from the 2010 DTM, and the scaling relationship between landslide area and its volume are further regressed. The relationship between volume and area are also determined for all the disturbed areas (V_L = 0.452A_L^1.242) and for the crown areas of the landslides (V_L = 2.510A_L^1.206). The uncertainty in estimated volume caused by use of the LiDAR DTMs is discussed, and the error in absolute volume estimation for landslides with an area >10⁵ m² is within 20%. The volume–area relationship obtained in this study is also validated in 11 small to medium‐sized catchments located outside the study area, and there is good agreement between the calculation from DTMs and the regression formula. By comparison of debris volumes estimated in this study with previous work, it is found that a wider volume variation exists that is directly proportional to the landslide area, especially under a higher scaling exponent. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

Simulation and control of the linked systems of water quantity–water quality–socio-economics in the Huaihe River basin     

Ming Dou  Qiting Zuo  Junxia Ma  Guiqiu Li 《水文科学杂志》2013,58(4):763-774

Abstract

This work makes explicit an algebraic expression giving the matrix of transient influence coefficients associated with a one-dimensional semi-confined aquifer model. The domain studied is divided into a series of connected and completely mixed compartments over which the governing equation is discretized. The discrete equations obtained are solved for the compartmental hydraulic head and used to derive the algebraic expression in question. The basic properties of the so-called algebraic influence coefficients are investigated. In particular, their consistency with the exact Green function is highlighted. Finally, the newly derived influence coefficients are applied to a simplified aquifer system in order to formulate and solve the problem of identifying illegal groundwater pumping.  相似文献   

全国主要构造区GPS水平运动负位错反演与应变积累特性   总被引：3，自引：0，他引：3  

张希  郝明  贾鹏  崔笃信 《地震研究》2013,36(1):1-8

利用2009～2011年全国GPS水平运动速度场资料,借助负位错反演,寻找新疆、青藏块体东北缘、川滇、华北地区主要活动断裂能量积累闭锁段,研究其积累速率、闭锁深度、分区分段差异性,及与强震孕育—发生的可能关系。结果表明:(1)新疆天山地区应变积累速率最强,平均闭锁深度也最深,约20.9km。其次为川滇地区,平均深度约16.3km。青藏块体东北缘存在一定程度应变积累,平均深度约15.7km。华北地区应变积累最弱,平均深度约16.0km;(2)南天山西段、川滇交界东部、红河断裂中段至滇西、祁连山断裂带西段、西秦岭北缘断裂甘青交界段、晋冀蒙交界区近期能量积累相对显著。  相似文献